Good job Steve! The suction yelp will come with practice, a lot of practice is my experience, but some things come quick to some and a little longer to others as is my case. I'm not quite as proficient as I would like, or I would take em to the woods. I have a little COPD thing goin on so I have a hard time storin up enough air to run a good sequence of yelps.
GOOD LUCK, GOD BLESS, AND STAY SAFE!